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<Head>
<Title>Boost Graph Library: astar_heuristic</Title>
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<H1>
<pre>
astar_heuristic&lt;Graph, CostType&gt;
</pre>
</H1>

This class is a default implementation of the <a
href="./AStarHeuristic.html">AStarHeuristic</a> concept.  It
implements a "zero" heuristic -- a heuristic function that returns a
cost of zero regardless of the vertex it is passed.

<h3>Model of</h3>

<a href="./AStarHeuristic.html">AStarHeuristic</a>

<H3>Template Parameters</H3>

<P>
<TABLE border>
<TR>
<th>Parameter</th><th>Description</th><th>Default</th>
</tr>

<TR><TD><TT>Graph</TT></TD>
<TD>
The type of the graph being searched.
</TD>
<TD></TD>
</TR>

<TR><TD><TT>CostType</TT></TD>
<TD>
A type that can be used with the <tt>compare</tt> and
<tt>combine</tt> functions passed to A*.  Typically an integer or
floating point type.
</TD>
<TD></TD>
</TR>

</table>

<H3>Where Defined</H3>

<P>
<a href="../../../boost/graph/astar_search.hpp">
<TT>boost/graph/astar_search.hpp</TT></a>

<h3>Member Functions</h3>

This class implements the single member function required by <a
href="./AStarHeuristic.html">AStarHeuristic</a>:

<table border>
<tr>
<th>Function</th><th>Description</th>
</tr>

<tr><td><tt>
CostType operator()(graph_traits&lt;Graph&gt;::vertex_descriptor u);
</tt></td><td>
Called for the target of every out edge of a vertex being examined.
Returns the cost, estimated by the heuristic, from vertex <tt>u</tt>
to a goal.
</td></tr>

</table>

<br>
<HR>
<TABLE>
<TR valign=top>
<TD nowrap>Copyright &copy; 2004</TD><TD>
<A HREF="http://cs.krisbeevers.com/">Kristopher Beevers</A>,
Rensselaer Polytechnic Institute (<A
HREF="mailto:beevek@cs.rpi.edu">beevek@cs.rpi.edu</A>)
</TD></TR></TABLE>

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